[CAS NO. 942918-07-2]  GSK1070916

GSK1070916 selectively inhibits Aurora B and Aurora C with K of 0.38 nM and 1.5 nM over Aurora A with K of 490 nM. Inhibition of Aurora B and Aurora C is time-dependent, with an enzyme-inhibitor dissociation half-life of >480 min and 270 min respectively. In addition, GSK1070916 is also a competitive inhibitor with respect to ATP. Human tumor cells treated with GSK1070916 shows dose-dependent inhibition of phosphorylation on serine 10 of Histone H3, a substrate specific for Aurora B. Moreover, GSK1070916 inhibits the proliferation of tumor cells with EC50 values of <10 nM in over 100 cell lines spanning a broad range of tumor types, with a median EC50 of 8 nM. Although GSK1070916 has potent activity against proliferating cells, a dramatic shift in potency is observed in primary, nondividing, normal human vein endothelial cells. Furthermore, GSK1070916-treated cells do not arrest in mitosis but instead fails to divide and become polyploid, ultimately leading to apoptosis. In another study, it is also reported high chromosome number associated with resistance to the inhibition of Aurora B and C suggests cells with a mechanism to bypass the high ploidy checkpoint are resistant to GSK1070916.